The House side of the Capitol has now reopened but the East Grand Staircase will remain closed between the first and third floors until further notice. All other areas have also returned to normal operations.

The AP reported that the House reconvened at noon for legislative business instead of 10 a.m., according to a statement from the Office of the Speaker.

Crews have collected samples to determine whether there was a potential exposure.

U.S. Capitol Police and the Architect of the Capitol are investigating.

During the closure, tours of the Capitol building were briefly suspended, and the south door was closed.

Update: House Side of Capitol reopen to Members and Staff with certain areas remaining closed. Tours are open. More: http://t.co/fAJGGdVuc6